Industrial machines, such as cold planers, pavement profilers, road milling machines, roadway planers, rotary mixers, and the like, are machines designed for scarifying, removing, mixing or reclaiming material from the surface of bituminous or concrete roadways and similar surfaces. These machines typically have a plurality of tracks or wheels which adjustably support and horizontally transport the machine along the surface of the road to be planed. Such milling machines also have a rotatable cutter or planing rotor that may be mechanically and/or hydraulically driven. Vertical adjustment of a milling machine with respect to the road surface may be provided by hydraulically adjustable rods that support the machine above its tracks or wheels.
The rotational speed of the cutter or rotor, or the rotor speed, of a conventional milling machine may be manually or automatically varied and adjusted by the operator. Typically, it may be desirable to maintain substantially constant rotor speed at the speed specified by the operator for at least the duration of a given milling task and/or until the operator chooses otherwise. However, changes in engine speed and engine load throughout the operation can cause unwanted variations in the rotor speed. Some milling machines, such as in U.S. Pat. No. 8,645,105 (“Parker”), provide variable transmissions which allow for variations in the engine speed without affecting rotor speed. However, these conventional systems do not further address fuel efficiency, which is another concern that can be adversely affected by variations in engine speed and engine load.
Accordingly, there is a need for improved solutions for controlling and maintaining a desired rotor speed of a milling machine, which also takes fuel consumption or efficiency into consideration. The present disclosure is directed at addressing one or more of this need. However, it should be appreciated that the solution of any particular problem is not a limitation on the scope of this disclosure or of the attached claims except to the extent express noted.